Synthesis
General procedure for the synthesis of 3-amino-5-nitroindazole from 2-fluoro-5-nitrobenzonitrile: 2-fluoro-5-nitrobenzonitrile (1.0 g, 6.02 mmol) was dissolved in n-butanol (20 mL). Subsequently, hydrazine hydrate (420 μL, 7.22 mmol) was added to this solution. The reaction mixture was stirred at 110 °C for 2 h and then cooled to room temperature. Dichloromethane (MC) was added to the reaction mixture and the precipitate precipitated was filtered to afford the target compound in 84% yield. The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 8.89 (d, 1H), 8.05 (dd, 1H), 7.34 (d, 2H), 5.98 (s, 2H). The molecular weight was measured as 178.15 by mass spectrometry.
References
[1] Patent: US2017/158642, 2017, A1. Location in patent: Paragraph 0075; 0076
[2] Bioorganic and Medicinal Chemistry Letters, 2005, vol. 15, # 23, p. 5293 - 5297
[3] Patent: US2004/9968, 2004, A1
[4] Bioorganic and Medicinal Chemistry Letters, 2011, vol. 21, # 1, p. 550 - 554
[5] Patent: WO2013/55984, 2013, A1. Location in patent: Paragraph 00342
